Many types of heat exchangers in use today employ two spaced header and tank constructions. Generally parallel, open ended tubes interconnect the header and tank constructions and are in fluid communication with the interior of each. In many cases, plate or serpentine fins are disposed across the tubes between the header and tank constructions. Typical examples of such heat exchangers are vehicular radiators, condensers, evaporators and the like although such heat exchangers may be found in many other applications as well.
In many of the applications, particularly applications such as that of a condenser, substantial pressures may be present on the interior of the heat exchanger. In order to withstand such pressures, there has been an increasing use of tubular header and tank constructions, that is, the use of a tube to serve both the function of a header and a tank. Usually, such tubular headers are cylindrical, having a generally circular cross section. An example may be found in commonly assigned U.S. Pat. No. 4,615,385.
As shown in that patent, the tubes extending between the two headers are in hydraulic parallel and that in turn means that the fluid on the interior of the heat exchanger makes but a single pass through the heat exchanger. In a number of instances, it may be desirable that the fluid within the heat exchanger make two or more passes across the heat exchanger. That may be accomplished by placing one or more baffles in the tubular headers, the number and and location of such baffles being dependent upon the number of passes desired as well as the specific application to which the heat exchanger is to be put.
Various baffles constructions have been proposed. In one, a simple circular slug or disc is placed in the tubular header and brazed or soldered in place.
In another construction, two slightly offset slots are formed on opposite sides of the header and semi-circular discs are introduced into the slots and have their sides in abutment within the header. They too, are then soldered or brazed in place.
Still another type of baffle is illustrated in Japanese patent publication No. Sho63-49193, published Apr. 2, 1988. In this construction, the tubular header is slotted along a diameter and a baffle having a large radius and a small radius is employed. The large radius is equal to the outer diameter of the tubular header while the small radius is equal to inner diameter of the header and both extend for 180.degree. about the baffle. The small radius is introduced into the header through the slot and the baffle is then brazed or soldered in place.
While such constructions do perform the function of baffles as generally desired, they are not completely foolproof. For one, the contact area between the header and the baffle is not as great as might be desired with the consequence that the braze potential is not as great as may be desired. The lesser braze potential means that leaks are more prone to form.
Furthermore, if a leakage path across the baffle exists, and such leakage path is not across a slot in the header, detection of leakage is difficult.
In addition, in a number of cases mentioned previously, the baffle must be inserted before the tubular header is made part of a heat exchanger core, thus placing a constraint on manufacturing flexibility.
The present invention is directed to overcoming one or more of the above problems.